With the economy on the uptick and demand for sophisticated technology on the rise, electronic part manufacturers are looking for ways to streamline production and boost performance while keeping costs at bay. PRÜFREX, an international supplier of advanced digital ignition systems for the automotive, marine, heating, and lawn and garden industries, is a case in point.
When PRÜFREX received a major new contract to produce small engine ignition control systems for forestry and garden machines, the company decided it was time to replace its existing semi-automated production line with a faster, more powerful alternative-one that would be able to handle a volume of approximately three million units per year.
One critical part of the application included resin-casting the ignition systems in a way that would ensure both their high-voltage insulation and their resistance to outside factors such as temperature, humidity, vibration, and demolition. To this end, PRÜFREX called on Scheugenpflug, a leading specialist for automated mixing, metering and dispensing systems.
The SolutionAfter carefully evaluating the application requirements, Scheugenpflug designed a fully automated production line to support the resin casting of electronic components in countless different configurations. With a 45 x 20-ft footprint, the system includes a linear transfer mechanism and a variety of process and measurement units, as well as several preheating and curing ovens loaded by a four-axis linear motion system.
The ignition controls are transferred in part bins via conveyor belt from preproduction to a test cell for camera inspection (and to record their model type and exact position). Then the system automatically selects and sets the precise resin dosage for each component before ferrying it on to preheating. From there, all parts make their way to a two-chamber vacuum dispensing station. In the first chamber, any remaining moisture and air bubbles are effectively eliminated. Next, the parts are transported under vacuum to the second main chamber where the actual casting and sealing takes place. With both chambers working in unison and in parallel, production can be significantly accelerated.
From the vacuum dispensing station, the parts make their way to a sensor-controlled unit that measures the casting levels with an accuracy of up to 0.004 in. The parts are then custom post-processed via an individually controlled, two-nozzle piston metering system.
“To streamline the process, we first dispense the exact same amount of resin onto all components,” explains Erich Scheugenpflug, CEO of Scheugenpflug Group. “Due to certain tolerances of the injection molding parts and a minimal reduction of resin levels as a result of the pressure difference after leaving the vacuum station, custom post-processing sometimes becomes necessary. The parts are therefore automatically transferred to a recasting station, and resin is cast under normal atmospheric pressure to reach the required level. The process is both very precise and extremely fast.”
After recasting and final control, the parts are forwarded by a four-axis linear transfer to one of three double-chamber curing ovens for custom curing. Since the delicate, fully filled components would be ruined by the slightest impact, the precision linear axis system must remain rigid in a completely horizontal position and guarantee smooth, vibration-free handling throughout the process. The oven doors even slide open through a precisely calibrated linear axis system.
High-Powered OutputWith maximum quality, speed and precision, Scheugenpflug’s state-of-the-art system is helping PRÜFREX meet the rapidly rising demand for its ignition systems. What’s more, the system is fully upgradable and well-suited to support the company’s future growth.
“Instant access to the supplier was key for us, and the responsiveness of Scheugenpflug’s project team was nothing short of amazing,” says PRÜFREX’s Alfred Pretzl. “Whether we wanted to share an idea or voice a concern, we were always able to reach their engineers within the hour. For example, when we started operating the recasting cell, we realized that we needed dispensing needles to ensure the accurate positioning of the dosage. We called Scheugenpflug and they had their modular solution meet the new requirement in a snap, which is testament not only to their outstanding customer service, but also to their flexibility and openness to innovation.”